ABSTRACT
We have developed a melt-blown fibrous construction of polybutylene/polypropylene in which we previously demonstrated keratocyte ingrowth and collagen synthesis in vitro. In the present studies, we evaluated this material in vivo in interlamellar corneal pockets for periods of up to six months. By day 42, the porous interstices of the disc were heavily populated with keratocytes. Extracellular matrix deposition occurred and there was a 5000-fold increase in total protein and a 1000-fold increase in total collagen over background. The cells within the disc continued to be synthetically active for the six months of our study. Discs remained in corneas for periods of up to one year without any extrusion. This material has great promise as a porous peripheral component of a keratoprosthetic device.
Subject(s)
Cornea/pathology , Polyenes , Polymers , Prostheses and Implants , Animals , Collagen/metabolism , Corneal Stroma/metabolism , Corneal Stroma/pathology , Corneal Stroma/surgery , Extracellular Matrix/metabolism , Extracellular Matrix/pathology , Eye Proteins/metabolism , Fibrosis , Microscopy, Fluorescence , Polypropylenes , RabbitsABSTRACT
We evaluated a polybutylene/polypropylene blend in a blown microfiber configuration in vitro for potential use as the peripheral area of a keratoprosthetic device. Material properties such as ultimate tensile strength and ultimate elongation were measured. Stromal fibroblasts were seeded onto the material in vitro, and cell proliferation between uncoated and Type I collagen coated discs did not differ significantly. Fibroblasts could be seen migrating along the fibers and also traversing the fibers. The synthesis of connective proteins was examined. Laminin, fibronectin, and Type I collagen were detected by day 8. The experiments demonstrate that stromal fibroblasts can adhere onto the fibers, proliferate, and synthesize connective tissue proteins. Experiments are now being conducted to further evaluate the material in vivo.
Subject(s)
Corneal Transplantation , Fibroblasts/cytology , Materials Testing , Polymers , Animals , Cell Division , Cells, Cultured , Collagen/biosynthesis , Corneal Stroma/cytology , Fibroblasts/ultrastructure , Fibronectins/biosynthesis , In Vitro Techniques , Laminin/biosynthesis , Polypropylenes , RabbitsABSTRACT
Based on the results of in vitro and in vivo experiments, we have determined that the optimal material for the central transparent portion of a perforating keratoprosthesis is a polyvinyl alcohol copolymer hydrogel. The material supports the maintenance and growth of corneal epithelium in vitro as shown by population doublings and transmission electron microscopy. Discs preseeded with epithelial cells were cultured in vitro and transplanted into rabbit corneas. The proliferation of these cells in vivo was demonstrated using 3H-thymidine. Other experiments showed that the preseeded cells not only migrated from the central disc onto the peripheral rim of the host cornea but also that host peripheral epithelial cells migrated onto the anterior surface of the disc. The experiments described in this paper demonstrate that corneal epithelial cells preseeded onto hydrogel discs and transplanted into rabbit corneas remain adherent and are capable of proliferating.
Subject(s)
Biocompatible Materials , Biopolymers , Cornea/physiology , Macromolecular Substances , Prostheses and Implants , Animals , Cell Movement , Cells, Cultured , Cornea/anatomy & histology , Cornea/metabolism , In Vitro Techniques , Protein Biosynthesis , RabbitsABSTRACT
Three synthetic peptides (compounds 4-6) were tested as substrates of pyroglutamylaminopeptidase. In addition, inhibition of the hydrolysis of these substrates by compounds 8 and 9 was also examined. The enzyme does not appreciably catalyze the hydrolysis of peptides with six-membered ureido rings at the amino terminus, but it tolerates well a five-membered ureido ring at this position.
